Gene expression of human beta defensins-1 and -2 is significantly reduced in non-inflamed keratinized oral tissue of smokers

Abstract

ObjectiveThe impact of smoking on the local innate immune response in the oral cavity, and, commonly, on oral health is actively discussed in the scientific literature. The aim of the present study was to evaluate possible effects of smoking on gene expression of human beta-defensin-1 and -2 in human gingival tissue. Material and methodsBiopsies of keratinized gingival tissues were taken from donors (with written informed consent) undergoing routine surgical treatment. Prior to the sample collection, participants with clinically healthy periodontium were classified as smokers (n=9) or non-smokers (n=9). Gingival tissue was homogenized, and total RNA was extracted and analysed by real-time RT-PCR for human beta-defensins-1-, -2-, and interleukins IL-1β- and IL-6-, as well as GAPDH-mRNA. The data obtained were analysed for significant differences using the Mann–Whitney-U test. ResultshBD-1- and hBD-2-, as well as IL-1β- and IL-6-mRNA were detected in all gingival samples. Expression of hBD-1 and -2 was significantly reduced by nearly 2.5-fold (p<0.05; Mann–Whitney) in gingival samples of smokers compared to control group specimens (non-smokers). In contrast, no significant differences of the gene expression of IL-6 and IL-1β were observed in human gingival tissue of smokers and non-smokers. ConclusionThe results presented here suggest that expression of human beta-defensins hBD-1 and -2, and, thus, the basal levels of innate immune defense reactions in the oral cavity are reduced by smoking.